Apomixis is tightly connected with hybridization and polyploidization. Despite a great potential in agriculture, the genetic mechanisms of apomixis are still poorly understood. Hybridization causes genetic instability including a restructuring of the repeatome, the fastest evolving part of plant genomes. Bursts of transposable elements due to hybridization-induced genomic shock may trigger a switch to apomixis. We will use sexual and apomictic parental Hieracium species in an extensive breeding program and compare artificial hybrids with natural apomicts of the same parentage / morphology as a model of hybrid speciation that may lead to the formation of apomictic lineages. Reproductive modes will be determined by flow cytometry, emasculation experiments and cytoembryological methods. We will analyze the repeatome by Next Generation Sequencing and use parental-specific repeats as cytogenetic markers to investigate genome repatterning following hybridization. The project will contribute to an understanding of mechanisms underlying the transition from sexual to apomictic reproduction.